Dual-Compressor Start Sequence for Pressure Interaction Control
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Solution Overview
Problem
In refrigerators with two compressors, the suction pressure and discharge pressure interactions between the compressors pose challenges for stable operation and reliability, necessitating a control method to minimize these effects.
Innovation Solution
A compressor control apparatus that starts the second compressor first and detects its top dead center before starting the first compressor, using control signals based on load and motor drive parameters to optimize the operation of both compressors in two stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two compressors are operated simultaneously in a two-stage refrigerator, then the compression capacity is improved, but the suction pressure and discharge pressure interactions cause instability and reliability issues
Solution Approach 1:
The control apparatus starts the second compressor first and detects its top dead center position before starting the first compressor. This preliminary action ensures that the second compressor is already operating when the first compressor starts, preventing harmful pressure interactions while maintaining high compression capacity through coordinated two-stage operation.
Solution Approach 2:
The system dynamically controls the start-up sequence and operation timing of the two compressors based on real-time pressure conditions and operational stage requirements. The control apparatus adjusts the operation of each compressor independently, allowing optimal performance while avoiding instability caused by simultaneous start-up or uncoordinated operation.
2Ease of operation
If the first compressor is started before the second compressor, then the start-up sequence is simplified, but the discharge pressure of the first compressor interacts harmfully with the suction pressure of the second compressor
Solution Approach 1:
The control apparatus implements a predetermined start-up sequence where the second compressor is started first and its top dead center is detected before initiating the first compressor. This preliminary action eliminates harmful pressure interactions by ensuring the second compressor is already operating when the first compressor starts, while the control apparatus automatically manages the sequence complexity.
Solution Approach 2:
Instead of starting the first compressor before the second (conventional sequence), the system inverts the start-up order by starting the second compressor first. This inversion prevents the discharge pressure of the first compressor from interacting with the suction pressure of the second compressor during start-up, eliminating the harmful effect.
3Reliability
If the second compressor is started first and top dead center is detected, then pressure interaction effects are minimized, but the control complexity increases
Solution Approach 1:
The control apparatus automatically performs the complex task of detecting the top dead center of the second compressor and timing the start-up of the first compressor accordingly. This preliminary detection and coordination is handled by the control system's existing monitoring capabilities, minimizing the need for additional complex control mechanisms while ensuring stable operation.
Solution Approach 2:
The control apparatus uses feedback from the second compressor's operational parameters (current, voltage, stroke position) to detect the top dead center and determine the optimal start-up timing for the first compressor. This feedback mechanism enables precise control of the start-up sequence, ensuring stability while using the control system's existing sensing and processing capabilities.
Data Source
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AI summary
There is disclosed herein a compressor control apparatus and method, and a refrigerator including the same. In a refrigerator (700) having two compressors (11,12) according to the embodiments of the present disclosure, two compressors (11,12) may be started with a time difference, thereby reducing an effect of the suction pressure and discharge pressure between mutual compressors. According to the embodiments of the present disclosure, the effect of the suction pressure and discharge pressure between mutual compressors (11,12) may be reduced to stably operate the compressors (11,12), thereby securing the reliability of the compressor (11,12) and enhancing the consumption power.